Ultrasonic Guided Wave Damage Localization in Hole-Structural Bearing Crossbeam Based on Improved RAPID Algorithm

The hole-structural bearing crossbeam plays an important role in high-speed trains. In the service process, however, the long-term fatigue load may lead to structural damage such as cracks, resulting in performance degradation and failure. Ultrasonic guided wave (GW) technology is one of the most effective damage localization methods in structural health monitoring (SHM), with a high damage sensitivity and wide monitoring range. To address the damage localization in bearing crossbeams, a modified reconstruction algorithm for probabilistic inspection of damage (RAPID) based on the corrected probability distribution function is proposed. First, the valid sensor paths affected by damage are obtained using damage index (DI) based on correlation analysis. Then, the positional relationships between valid paths and damage are classified based on the time of flight (TOF). Finally, the damage diagnostic image and localization are obtained by fusion imaging using the corresponding probability distribution functions and shape factors, depending on different types of the path. The effectiveness was verified by numerical simulation and experiment. By taking the crossbeam of the high-speed train as the research object, through the static simulation of the crossbeam stress distribution under load, the damaged hot-spots area is obtained, and the sensor network is designed. And then, the SHM experimental system is constructed to perform damage localization experiments. The localization absolute error was less than 8 mm. Experimental results show that the proposed method can effectively locate the damage position in the crossbeam and has better accuracy and reliability than the traditional RAPID algorithm.